audiopolicy: Implement API for querying A2DP offload formats

Add support in AudioPolicyManager to return supported encoding
formats for A2DP on the primary HAL. Current implementation is
to query prop defined and convert this to a list of audio formats

Bug: 111812273
Test: make
Change-Id: Ic3ea72e19aa4c0bd4c156f62e45e6225f9ce6b11
9 files changed